@media(max-width:850px){
    .info-slider {
        text-align: center;
        margin: 6% auto;
        position: relative;
        top: 30%;
        color: #fff;    
        font-family: Verdana;
        letter-spacing: 1px;
    }

    .slider-back{
        background: rgba(39, 39, 39, .8);
        height: 500px;
        width: 100%;
        position: absolute;
    }
}

@media(min-width:851px){
    .info-slider {
        text-align: center;
        margin: 6% auto;
        position: relative;
        top: 30%;
        /*height: inherit;*/
        color: #fff;    
        font-family: Verdana;
        letter-spacing: 1px; 
    }

    .slider-back{
        background: rgba(94, 94, 94, 0.8);
        height: 400px;
        width: 100%;
        position: absolute;
    }
}

@media(min-width:768px){
    #flexslider {
        height: 100%;
        overflow: hidden;
    }
}

@media(max-width:768px){
    #flexslider {
        height: 100%;
        overflow: hidden;
    }
}